define counter 0
define bar (|x|)
    counter := counter + 1
    format #t "bar called x=~s counter=~s!~%~!" x counter
define (foo #!optional (x 10))
  counter := counter + 1
  format #t "foo called x=~s counter=~s!~%~!" x counter
define baz (|x y|) (list y x)
foo
foo 5
foo
bar 11
format #t "baz 9 8 => ~w~%~!" (baz 9 8)

# Output: foo called x=10 counter=1!
# Output: foo called x=5 counter=2!
# Output: foo called x=10 counter=3!
# Output: bar called x=11 counter=4!
# Output: baz 9 8 => (8 9)
